Faker vs LocalStack

Free and open source

From $35 per user/month (indicative, Pro)

Free and open source. You pay in engineering time and CI minutes.

Community edition is genuinely useful; Pro adds services such as RDS, ECS and advanced IAM enforcement.

Everything, self-hosted

Community edition covers the most-used AWS services and is free.

Category standard

OSS community · since 2010

Category standard

LocalStack · since 2017

• Realistic, locale-aware data catches layout bugs that 'test test test' never will.
• Seedable, so generated data is reproducible when a test fails.
• Available in every major language with a similar API.

• Integration tests against AWS services run offline in seconds at no cloud cost.
• Removes the shared-sandbox-account contention that plagues cloud teams.
• Works with Terraform and CDK, so infrastructure code is testable.

• Generated data has no referential integrity or business rules — that is your job.
• Random data makes failures harder to reproduce unless you seed deliberately.
• Not a substitute for production-shaped data at realistic volume.

• Emulation is not identical to AWS; some behaviours and IAM semantics differ.
• Many services are Pro-only.
• Keeping up with AWS feature changes means occasional gaps.

Every project that needs fixtures more realistic than placeholder strings.

AWS-native teams whose tests currently depend on a shared cloud account.